The present invention relates to a sound increase apparatus which is capable of improving sound quality of an intake sound that is generated from an inlet system of internal combustion engine, and capable of increasing the intake sound over wide range of frequencies.
In recent years, there have been proposed and developed various sound increase apparatus capable of improvement of sound quality and increase of the intake sound generated from the inlet system of internal combustion engine. One such sound increase apparatus has been disclosed in Japanese Patent Provisional Publication No. 2004-218458 (hereinafter is referred to as “JP2004-218458”). In JP2004-218458, an opening is formed on a side wall of an air induction part that forms an intake flow path, and the opening and a dash panel are connected by flexible tubes. Then, the intake sound having pressure oscillations resonates with the dash panel, and the intake sound is conveyed into a vehicle cabin. And thus, a sporty intake sound can be rendered in the cabin.